/* S = (A * v^u) ^ b % N
* this is our shared key (server premaster secret)
*/
mpi_t
_gnutls_calc_srp_S1 (mpi_t A, mpi_t b, mpi_t u, mpi_t v, mpi_t n)
{
mpi_t tmp1 = NULL, tmp2 = NULL;
mpi_t S = NULL;
S = _gnutls_mpi_alloc_like (n);
if (S == NULL)
return NULL;
tmp1 = _gnutls_mpi_alloc_like (n);
tmp2 = _gnutls_mpi_alloc_like (n);
if (tmp1 == NULL || tmp2 == NULL)
goto freeall;
_gnutls_mpi_powm (tmp1, v, u, n);
_gnutls_mpi_mulm (tmp2, A, tmp1, n);
_gnutls_mpi_powm (S, tmp2, b, n);
_gnutls_mpi_release (&tmp1);
_gnutls_mpi_release (&tmp2);
return S;
freeall:
_gnutls_mpi_release (&tmp1);
_gnutls_mpi_release (&tmp2);
return NULL;
}
/* S = (B - k*g^x) ^ (a + u * x) % N
* this is our shared key (client premaster secret)
*/
bigint_t
_gnutls_calc_srp_S2 (bigint_t B, bigint_t g, bigint_t x, bigint_t a,
bigint_t u, bigint_t n)
{
bigint_t S = NULL, tmp1 = NULL, tmp2 = NULL;
bigint_t tmp4 = NULL, tmp3 = NULL, k = NULL;
S = _gnutls_mpi_alloc_like (n);
if (S == NULL)
return NULL;
tmp1 = _gnutls_mpi_alloc_like (n);
tmp2 = _gnutls_mpi_alloc_like (n);
tmp3 = _gnutls_mpi_alloc_like (n);
if (tmp1 == NULL || tmp2 == NULL || tmp3 == NULL)
{
goto freeall;
}
k = _gnutls_calc_srp_u (n, g, n);
if (k == NULL)
{
gnutls_assert ();
goto freeall;
}
_gnutls_mpi_powm (tmp1, g, x, n); /* g^x */
_gnutls_mpi_mulm (tmp3, tmp1, k, n); /* k*g^x mod n */
_gnutls_mpi_subm (tmp2, B, tmp3, n);
tmp4 = _gnutls_mpi_alloc_like (n);
if (tmp4 == NULL)
goto freeall;
_gnutls_mpi_mul (tmp1, u, x);
_gnutls_mpi_add (tmp4, a, tmp1);
_gnutls_mpi_powm (S, tmp2, tmp4, n);
_gnutls_mpi_release (&tmp1);
_gnutls_mpi_release (&tmp2);
_gnutls_mpi_release (&tmp3);
_gnutls_mpi_release (&tmp4);
_gnutls_mpi_release (&k);
return S;
freeall:
_gnutls_mpi_release (&k);
_gnutls_mpi_release (&tmp1);
_gnutls_mpi_release (&tmp2);
_gnutls_mpi_release (&tmp3);
_gnutls_mpi_release (&tmp4);
_gnutls_mpi_release (&S);
return NULL;
}
/* A = g^a % N
* returns A and a (which is random)
*/
bigint_t
_gnutls_calc_srp_A (bigint_t * a, bigint_t g, bigint_t n)
{
bigint_t tmpa;
bigint_t A;
int bits;
bits = _gnutls_mpi_get_nbits (n);
tmpa = _gnutls_mpi_randomize (NULL, bits, GNUTLS_RND_RANDOM);
A = _gnutls_mpi_new (bits);
if (A == NULL)
{
gnutls_assert ();
_gnutls_mpi_release (&tmpa);
return NULL;
}
_gnutls_mpi_powm (A, g, tmpa, n);
if (a != NULL)
*a = tmpa;
else
_gnutls_mpi_release (&tmpa);
return A;
}
/* A = g^a % N
* returns A and a (which is random)
*/
mpi_t
_gnutls_calc_srp_A (mpi_t * a, mpi_t g, mpi_t n)
{
mpi_t tmpa;
mpi_t A;
int bits;
bits = _gnutls_mpi_get_nbits (n);
tmpa = _gnutls_mpi_snew (bits);
if (tmpa == NULL)
{
gnutls_assert ();
return NULL;
}
_gnutls_mpi_randomize (tmpa, bits, GCRY_STRONG_RANDOM);
A = _gnutls_mpi_snew (bits);
if (A == NULL)
{
gnutls_assert ();
_gnutls_mpi_release (&tmpa);
return NULL;
}
_gnutls_mpi_powm (A, g, tmpa, n);
if (a != NULL)
*a = tmpa;
else
_gnutls_mpi_release (&tmpa);
return A;
}
/* A = g^a % N
* returns A and a (which is random)
*/
bigint_t _gnutls_calc_srp_A(bigint_t * a, bigint_t g, bigint_t n)
{
bigint_t tmpa;
bigint_t A;
int ret;
ret = _gnutls_mpi_init_multi(&A, &tmpa, NULL);
if (ret < 0) {
gnutls_assert();
return NULL;
}
_gnutls_mpi_random_modp(tmpa, n, GNUTLS_RND_RANDOM);
ret = _gnutls_mpi_powm(A, g, tmpa, n);
if (ret < 0)
goto error;
if (a != NULL)
*a = tmpa;
else
_gnutls_mpi_release(&tmpa);
return A;
error:
_gnutls_mpi_release(&tmpa);
_gnutls_mpi_release(&A);
return NULL;
}
/****************
* Choose a random value b and calculate B = (k* v + g^b) % N.
* where k == SHA1(N|g)
* Return: B and if ret_b is not NULL b.
*/
bigint_t
_gnutls_calc_srp_B(bigint_t * ret_b, bigint_t g, bigint_t n, bigint_t v)
{
bigint_t tmpB = NULL, tmpV = NULL;
bigint_t b = NULL, B = NULL, k = NULL;
int ret;
/* calculate: B = (k*v + g^b) % N
*/
ret = _gnutls_mpi_init_multi(&tmpV, &tmpB, &B, &b, NULL);
if (ret < 0)
return NULL;
_gnutls_mpi_random_modp(b, n, GNUTLS_RND_RANDOM);
k = _gnutls_calc_srp_u(n, g, n);
if (k == NULL) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_mulm(tmpV, k, v, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_powm(tmpB, g, b, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_addm(B, tmpV, tmpB, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
_gnutls_mpi_release(&k);
_gnutls_mpi_release(&tmpB);
_gnutls_mpi_release(&tmpV);
if (ret_b)
*ret_b = b;
else
_gnutls_mpi_release(&b);
return B;
error:
_gnutls_mpi_release(&b);
_gnutls_mpi_release(&B);
_gnutls_mpi_release(&k);
_gnutls_mpi_release(&tmpB);
_gnutls_mpi_release(&tmpV);
return NULL;
}
/* returns the public value (X), and the secret (ret_x).
*/
mpi_t
gnutls_calc_dh_secret (mpi_t * ret_x, mpi_t g, mpi_t prime)
{
mpi_t e, x;
int x_size = _gnutls_mpi_get_nbits (prime) - 1;
/* The size of the secret key is less than
* prime/2
*/
if (x_size > MAX_BITS || x_size <= 0)
{
gnutls_assert ();
return NULL;
}
x = _gnutls_mpi_new (x_size);
if (x == NULL)
{
gnutls_assert ();
if (ret_x)
*ret_x = NULL;
return NULL;
}
/* FIXME: (x_size/8)*8 is there to overcome a bug in libgcrypt
* which does not really check the bits given but the bytes.
*/
do
{
_gnutls_mpi_randomize (x, (x_size / 8) * 8, GCRY_STRONG_RANDOM);
/* Check whether x is zero.
*/
}
while (_gnutls_mpi_cmp_ui (x, 0) == 0);
e = _gnutls_mpi_alloc_like (prime);
if (e == NULL)
{
gnutls_assert ();
if (ret_x)
*ret_x = NULL;
_gnutls_mpi_release (&x);
return NULL;
}
_gnutls_mpi_powm (e, g, x, prime);
if (ret_x)
*ret_x = x;
else
_gnutls_mpi_release (&x);
return e;
}
/* returns the blinded c and the inverse of a random
* number r;
*/
static bigint_t
rsa_blind (bigint_t c, bigint_t e, bigint_t n, bigint_t * _ri)
{
bigint_t nc = NULL, r = NULL, ri = NULL;
/* nc = c*(r^e)
* ri = r^(-1)
*/
nc = _gnutls_mpi_alloc_like (n);
if (nc == NULL)
{
gnutls_assert ();
return NULL;
}
ri = _gnutls_mpi_alloc_like (n);
if (nc == NULL)
{
gnutls_assert ();
goto fail;
}
r = _gnutls_mpi_randomize (NULL, _gnutls_mpi_get_nbits (n),
GNUTLS_RND_NONCE);
if (r == NULL)
{
gnutls_assert ();
goto fail;
}
/* invert r */
if (mpz_invert (ri, r, n) == 0)
{
gnutls_assert ();
goto fail;
}
/* r = r^e */
_gnutls_mpi_powm (r, r, e, n);
_gnutls_mpi_mulm (nc, c, r, n);
*_ri = ri;
_gnutls_mpi_release (&r);
return nc;
fail:
_gnutls_mpi_release (&nc);
_gnutls_mpi_release (&r);
return NULL;
}
/* S = (A * v^u) ^ b % N
* this is our shared key (server premaster secret)
*/
bigint_t
_gnutls_calc_srp_S1(bigint_t A, bigint_t b, bigint_t u, bigint_t v,
bigint_t n)
{
bigint_t tmp1 = NULL, tmp2 = NULL;
bigint_t S = NULL;
int ret;
ret = _gnutls_mpi_init_multi(&S, &tmp1, &tmp2, NULL);
if (ret < 0)
return NULL;
ret = _gnutls_mpi_powm(tmp1, v, u, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_mulm(tmp2, A, tmp1, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
_gnutls_mpi_powm(S, tmp2, b, n);
_gnutls_mpi_release(&tmp1);
_gnutls_mpi_release(&tmp2);
return S;
error:
_gnutls_mpi_release(&S);
_gnutls_mpi_release(&tmp1);
_gnutls_mpi_release(&tmp2);
return NULL;
}
int
_gnutls_srp_gx (opaque * text, size_t textsize, opaque ** result,
bigint_t g, bigint_t prime, gnutls_alloc_function galloc_func)
{
bigint_t x, e;
size_t result_size;
int ret;
if (_gnutls_mpi_scan_nz (&x, text, textsize))
{
gnutls_assert ();
return GNUTLS_E_MPI_SCAN_FAILED;
}
e = _gnutls_mpi_alloc_like (prime);
if (e == NULL)
{
gnutls_assert ();
_gnutls_mpi_release (&x);
return GNUTLS_E_MEMORY_ERROR;
}
/* e = g^x mod prime (n) */
_gnutls_mpi_powm (e, g, x, prime);
_gnutls_mpi_release (&x);
ret = _gnutls_mpi_print (e, NULL, &result_size);
if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
{
*result = galloc_func (result_size);
if ((*result) == NULL)
return GNUTLS_E_MEMORY_ERROR;
_gnutls_mpi_print (e, *result, &result_size);
ret = result_size;
}
else
{
gnutls_assert ();
ret = GNUTLS_E_MPI_PRINT_FAILED;
}
_gnutls_mpi_release (&e);
return ret;
}
static int
_gnutls_srp_gx(uint8_t * text, size_t textsize, uint8_t ** result,
bigint_t g, bigint_t prime)
{
bigint_t x, e = NULL;
size_t result_size;
int ret;
if (_gnutls_mpi_init_scan_nz(&x, text, textsize)) {
gnutls_assert();
return GNUTLS_E_MPI_SCAN_FAILED;
}
ret = _gnutls_mpi_init(&e);
if (ret < 0)
goto cleanup;
/* e = g^x mod prime (n) */
ret = _gnutls_mpi_powm(e, g, x, prime);
if (ret < 0)
goto cleanup;
ret = _gnutls_mpi_print(e, NULL, &result_size);
if (ret == GNUTLS_E_SHORT_MEMORY_BUFFER) {
*result = gnutls_malloc(result_size);
if ((*result) == NULL) {
ret = GNUTLS_E_MEMORY_ERROR;
goto cleanup;
}
ret = _gnutls_mpi_print(e, *result, &result_size);
if (ret < 0)
goto cleanup;
ret = result_size;
} else {
gnutls_assert();
ret = GNUTLS_E_MPI_PRINT_FAILED;
}
cleanup:
_gnutls_mpi_release(&e);
_gnutls_mpi_release(&x);
return ret;
}
mpi_t
gnutls_calc_dh_key (mpi_t f, mpi_t x, mpi_t prime)
{
mpi_t k;
int bits;
bits = _gnutls_mpi_get_nbits (prime);
if (bits <= 0 || bits > MAX_BITS)
{
gnutls_assert ();
return NULL;
}
k = _gnutls_mpi_alloc_like (prime);
if (k == NULL)
return NULL;
_gnutls_mpi_powm (k, f, x, prime);
return k;
}
int
_gnutls_srp_gx (opaque * text, size_t textsize, opaque ** result,
mpi_t g, mpi_t prime, gnutls_alloc_function galloc_func)
{
mpi_t x, e;
size_t result_size;
if (_gnutls_mpi_scan_nz (&x, text, &textsize))
{
gnutls_assert ();
return GNUTLS_E_MPI_SCAN_FAILED;
}
e = _gnutls_mpi_alloc_like (prime);
if (e == NULL)
{
gnutls_assert ();
_gnutls_mpi_release (&x);
return GNUTLS_E_MEMORY_ERROR;
}
/* e = g^x mod prime (n) */
_gnutls_mpi_powm (e, g, x, prime);
_gnutls_mpi_release (&x);
_gnutls_mpi_print (NULL, &result_size, e);
if (result != NULL)
{
*result = galloc_func (result_size);
if ((*result) == NULL)
return GNUTLS_E_MEMORY_ERROR;
_gnutls_mpi_print (*result, &result_size, e);
}
_gnutls_mpi_release (&e);
return result_size;
}
/****************
* Choose a random value b and calculate B = (k* v + g^b) % N.
* where k == SHA1(N|g)
* Return: B and if ret_b is not NULL b.
*/
mpi_t
_gnutls_calc_srp_B (mpi_t * ret_b, mpi_t g, mpi_t n, mpi_t v)
{
mpi_t tmpB = NULL, tmpV = NULL;
mpi_t b = NULL, B = NULL, k = NULL;
int bits;
/* calculate: B = (k*v + g^b) % N
*/
bits = _gnutls_mpi_get_nbits (n);
b = _gnutls_mpi_snew (bits);
if (b == NULL)
{
gnutls_assert ();
return NULL;
}
tmpV = _gnutls_mpi_alloc_like (n);
if (tmpV == NULL)
{
gnutls_assert ();
goto error;
}
_gnutls_mpi_randomize (b, bits, GCRY_STRONG_RANDOM);
tmpB = _gnutls_mpi_snew (bits);
if (tmpB == NULL)
{
gnutls_assert ();
goto error;
}
B = _gnutls_mpi_snew (bits);
if (B == NULL)
{
gnutls_assert ();
goto error;
}
k = _gnutls_calc_srp_u (n, g, n);
if (k == NULL)
{
gnutls_assert ();
goto error;
}
_gnutls_mpi_mulm (tmpV, k, v, n);
_gnutls_mpi_powm (tmpB, g, b, n);
_gnutls_mpi_addm (B, tmpV, tmpB, n);
_gnutls_mpi_release (&k);
_gnutls_mpi_release (&tmpB);
_gnutls_mpi_release (&tmpV);
if (ret_b)
*ret_b = b;
else
_gnutls_mpi_release (&b);
return B;
error:
_gnutls_mpi_release (&b);
_gnutls_mpi_release (&B);
_gnutls_mpi_release (&k);
_gnutls_mpi_release (&tmpB);
_gnutls_mpi_release (&tmpV);
return NULL;
}
static int
wrap_nettle_pk_verify_params(gnutls_pk_algorithm_t algo,
const gnutls_pk_params_st * params)
{
int ret;
switch (algo) {
case GNUTLS_PK_RSA:
{
bigint_t t1 = NULL, t2 = NULL;
if (params->params_nr != RSA_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
t1 = _gnutls_mpi_new(256);
if (t1 == NULL)
return
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_mulm(t1, params->params[RSA_PRIME1],
params->params[RSA_PRIME2],
params->params[RSA_MODULUS]);
if (_gnutls_mpi_cmp_ui(t1, 0) != 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
mpz_invert(TOMPZ(t1),
TOMPZ(params->params[RSA_PRIME2]),
TOMPZ(params->params[RSA_PRIME1]));
if (_gnutls_mpi_cmp(t1, params->params[RSA_COEF])
!= 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
/* [RSA_PRIME1] = d % p-1, [RSA_PRIME2] = d % q-1 */
_gnutls_mpi_sub_ui(t1, params->params[RSA_PRIME1],
1);
t2 = _gnutls_mpi_mod(params->params[RSA_PRIV], t1);
if (t2 == NULL) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E1], t2) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
_gnutls_mpi_sub_ui(t1, params->params[RSA_PRIME2],
1);
_gnutls_mpi_release(&t2);
t2 = _gnutls_mpi_mod(params->params[RSA_PRIV], t1);
if (t2 == NULL) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E2], t2) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
ret = 0;
rsa_cleanup:
_gnutls_mpi_release(&t1);
_gnutls_mpi_release(&t2);
}
break;
case GNUTLS_PK_DSA:
{
bigint_t t1 = NULL;
if (params->params_nr != DSA_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
t1 = _gnutls_mpi_new(256);
if (t1 == NULL)
return
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_powm(t1, params->params[DSA_G],
params->params[DSA_X],
params->params[DSA_P]);
if (_gnutls_mpi_cmp(t1, params->params[DSA_Y]) !=
0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto dsa_cleanup;
}
ret = 0;
dsa_cleanup:
_gnutls_mpi_release(&t1);
}
break;
case GNUTLS_PK_EC:
{
struct ecc_point r, pub;
struct ecc_scalar priv;
mpz_t x1, y1, x2, y2;
const struct ecc_curve *curve;
if (params->params_nr != ECC_PRIVATE_PARAMS)
return
gnutls_assert_val
(GNUTLS_E_INVALID_REQUEST);
curve = get_supported_curve(params->flags);
if (curve == NULL)
return
gnutls_assert_val
(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
ret = _ecc_params_to_pubkey(params, &pub, curve);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _ecc_params_to_privkey(params, &priv, curve);
if (ret < 0) {
ecc_point_clear(&pub);
return gnutls_assert_val(ret);
}
ecc_point_init(&r, curve);
/* verify that x,y lie on the curve */
ret =
ecc_point_set(&r, TOMPZ(params->params[ECC_X]),
TOMPZ(params->params[ECC_Y]));
if (ret == 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ecc_point_clear(&r);
ecc_point_init(&r, curve);
ecc_point_mul_g(&r, &priv);
mpz_init(x1);
mpz_init(y1);
ecc_point_get(&r, x1, y1);
ecc_point_clear(&r);
mpz_init(x2);
mpz_init(y2);
ecc_point_get(&pub, x2, y2);
/* verify that k*(Gx,Gy)=(x,y) */
if (mpz_cmp(x1, x2) != 0 || mpz_cmp(y1, y2) != 0) {
ret =
gnutls_assert_val
(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ret = 0;
ecc_cleanup:
ecc_scalar_clear(&priv);
ecc_point_clear(&pub);
}
break;
default:
ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}
return ret;
}
/* This is used for DH or ECDH key derivation. In DH for example
* it is given the peers Y and our x, and calculates Y^x
*/
static int _wrap_nettle_pk_derive(gnutls_pk_algorithm_t algo,
gnutls_datum_t * out,
const gnutls_pk_params_st * priv,
const gnutls_pk_params_st * pub)
{
int ret;
switch (algo) {
case GNUTLS_PK_DH: {
bigint_t f, x, prime;
bigint_t k = NULL, ff = NULL;
unsigned int bits;
f = pub->params[DH_Y];
x = priv->params[DH_X];
prime = priv->params[DH_P];
ret = _gnutls_mpi_init_multi(&k, &ff, NULL);
if (ret < 0)
return gnutls_assert_val(ret);
ret = _gnutls_mpi_modm(ff, f, prime);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = _gnutls_mpi_add_ui(ff, ff, 1);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
/* check if f==0,1,p-1.
* or (ff=f+1) equivalently ff==1,2,p */
if ((_gnutls_mpi_cmp_ui(ff, 2) == 0)
|| (_gnutls_mpi_cmp_ui(ff, 1) == 0)
|| (_gnutls_mpi_cmp(ff, prime) == 0)) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto dh_cleanup;
}
/* prevent denial of service */
bits = _gnutls_mpi_get_nbits(prime);
if (bits == 0 || bits > MAX_DH_BITS) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto dh_cleanup;
}
ret = _gnutls_mpi_powm(k, f, x, prime);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = _gnutls_mpi_dprint(k, out);
if (ret < 0) {
gnutls_assert();
goto dh_cleanup;
}
ret = 0;
dh_cleanup:
_gnutls_mpi_release(&ff);
zrelease_temp_mpi_key(&k);
if (ret < 0)
goto cleanup;
break;
}
case GNUTLS_PK_EC:
{
struct ecc_scalar ecc_priv;
struct ecc_point ecc_pub;
const struct ecc_curve *curve;
out->data = NULL;
curve = get_supported_curve(priv->flags);
if (curve == NULL)
return
gnutls_assert_val
(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
ret = _ecc_params_to_pubkey(pub, &ecc_pub, curve);
if (ret < 0)
return gnutls_assert_val(ret);
ret =
_ecc_params_to_privkey(priv, &ecc_priv, curve);
if (ret < 0) {
ecc_point_clear(&ecc_pub);
return gnutls_assert_val(ret);
}
out->size = gnutls_ecc_curve_get_size(priv->flags);
/*ecc_size(curve)*sizeof(mp_limb_t); */
out->data = gnutls_malloc(out->size);
if (out->data == NULL) {
ret =
gnutls_assert_val
(GNUTLS_E_MEMORY_ERROR);
goto ecc_cleanup;
}
ecc_shared_secret(&ecc_priv, &ecc_pub, out->data,
out->size);
ecc_cleanup:
ecc_point_clear(&ecc_pub);
ecc_scalar_zclear(&ecc_priv);
if (ret < 0)
goto cleanup;
break;
}
default:
gnutls_assert();
ret = GNUTLS_E_INTERNAL_ERROR;
goto cleanup;
}
ret = 0;
cleanup:
return ret;
}
/* Check if N is a prime and G a generator of the
* group. This is check only done if N is big enough.
* Otherwise only the included parameters must be used.
*/
static int
group_check_g_n (mpi_t g, mpi_t n)
{
mpi_t q = NULL, two = NULL, w = NULL;
int ret;
if (_gnutls_mpi_get_nbits (n) < 2048)
{
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* N must be of the form N=2q+1
* where q is also a prime.
*/
if (_gnutls_prime_check (n, 0) != 0)
{
_gnutls_dump_mpi ("no prime N: ", n);
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
two = _gnutls_mpi_new (4);
if (two == NULL)
{
gnutls_assert ();
return GNUTLS_E_MEMORY_ERROR;
}
q = _gnutls_mpi_alloc_like (n);
if (q == NULL)
{
gnutls_assert ();
ret = GNUTLS_E_MEMORY_ERROR;
goto error;
}
/* q = n-1
*/
_gnutls_mpi_sub_ui (q, n, 1);
/* q = q/2, remember that q is divisible by 2 (prime - 1)
*/
_gnutls_mpi_set_ui (two, 2);
_gnutls_mpi_div (q, NULL, q, two, 0);
if (_gnutls_prime_check (q, 0) != 0)
{
/* N was not on the form N=2q+1, where q = prime
*/
_gnutls_dump_mpi ("no prime Q: ", q);
gnutls_assert ();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* We also check whether g is a generator,
*/
/* check if g < q < N
*/
if (_gnutls_mpi_cmp (g, q) >= 0)
{
gnutls_assert ();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
w = _gnutls_mpi_alloc_like (q);
if (w == NULL)
{
gnutls_assert ();
ret = GNUTLS_E_MEMORY_ERROR;
goto error;
}
/* check if g^q mod N == N-1
* w = g^q mod N
*/
_gnutls_mpi_powm (w, g, q, n);
/* w++
*/
_gnutls_mpi_add_ui (w, w, 1);
if (_gnutls_mpi_cmp (w, n) != 0)
{
gnutls_assert ();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
ret = 0;
error:
_gnutls_mpi_release (&q);
_gnutls_mpi_release (&two);
_gnutls_mpi_release (&w);
return ret;
}
/* Check if N is a prime and G a generator of the
* group. This check is only done if N is big enough.
* Otherwise only the included parameters must be used.
*/
static int
group_check_g_n(gnutls_session_t session, bigint_t g, bigint_t n)
{
bigint_t q = NULL, two = NULL, w = NULL;
int ret;
if (_gnutls_mpi_get_nbits(n) < (session->internals.srp_prime_bits
? session->internals.srp_prime_bits
: 2048)) {
gnutls_assert();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
/* N must be of the form N=2q+1
* where q is also a prime.
*/
if (_gnutls_prime_check(n) != 0) {
_gnutls_mpi_log("no prime N: ", n);
gnutls_assert();
return GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
}
ret = _gnutls_mpi_init_multi(&two, &q, &w, NULL);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* q = n-1
*/
ret = _gnutls_mpi_sub_ui(q, n, 1);
if (ret < 0) {
gnutls_assert();
goto error;
}
/* q = q/2, remember that q is divisible by 2 (prime - 1)
*/
ret = _gnutls_mpi_set_ui(two, 2);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_div(q, q, two);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (_gnutls_prime_check(q) != 0) {
/* N was not on the form N=2q+1, where q = prime
*/
_gnutls_mpi_log("no prime Q: ", q);
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
/* We also check whether g is a generator,
*/
/* check if g < q < N
*/
if (_gnutls_mpi_cmp(g, q) >= 0) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
/* check if g^q mod N == N-1
* w = g^q mod N
*/
ret = _gnutls_mpi_powm(w, g, q, n);
if (ret < 0) {
gnutls_assert();
goto error;
}
/* w++
*/
ret = _gnutls_mpi_add_ui(w, w, 1);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (_gnutls_mpi_cmp(w, n) != 0) {
gnutls_assert();
ret = GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER;
goto error;
}
ret = 0;
error:
_gnutls_mpi_release(&q);
_gnutls_mpi_release(&two);
_gnutls_mpi_release(&w);
return ret;
}
static int
wrap_nettle_pk_verify_params (gnutls_pk_algorithm_t algo,
const gnutls_pk_params_st * params)
{
int ret;
switch (algo)
{
case GNUTLS_PK_RSA:
{
bigint_t t1 = NULL, t2 = NULL;
if (params->params_nr != RSA_PRIVATE_PARAMS)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
t1 = _gnutls_mpi_new (256);
if (t1 == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_mulm (t1, params->params[RSA_PRIME1], params->params[RSA_PRIME2], params->params[RSA_MODULUS]);
if (_gnutls_mpi_cmp_ui(t1, 0) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
mpz_invert (TOMPZ(t1), TOMPZ (params->params[RSA_PRIME2]), TOMPZ (params->params[RSA_PRIME1]));
if (_gnutls_mpi_cmp(t1, params->params[RSA_COEF]) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
/* [RSA_PRIME1] = d % p-1, [RSA_PRIME2] = d % q-1 */
_gnutls_mpi_sub_ui (t1, params->params[RSA_PRIME1], 1);
t2 = _gnutls_mpi_mod (params->params[RSA_PRIV], t1);
if (t2 == NULL)
{
ret = gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E1], t2) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
_gnutls_mpi_sub_ui (t1, params->params[RSA_PRIME2], 1);
_gnutls_mpi_release(&t2);
t2 = _gnutls_mpi_mod (params->params[RSA_PRIV], t1);
if (t2 == NULL)
{
ret = gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
goto rsa_cleanup;
}
if (_gnutls_mpi_cmp(params->params[RSA_E2], t2) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto rsa_cleanup;
}
ret = 0;
rsa_cleanup:
_gnutls_mpi_release(&t1);
_gnutls_mpi_release(&t2);
}
break;
case GNUTLS_PK_DSA:
{
bigint_t t1 = NULL;
if (params->params_nr != DSA_PRIVATE_PARAMS)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
t1 = _gnutls_mpi_new (256);
if (t1 == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
_gnutls_mpi_powm (t1, params->params[DSA_G], params->params[DSA_X], params->params[DSA_P]);
if (_gnutls_mpi_cmp(t1, params->params[DSA_Y]) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto dsa_cleanup;
}
ret = 0;
dsa_cleanup:
_gnutls_mpi_release(&t1);
}
break;
case GNUTLS_PK_EC:
{
int curve = params->flags;
ecc_key ecc_priv;
ecc_point *R;
ecc_point zero;
if (params->params_nr != ECC_PRIVATE_PARAMS)
return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
if (is_supported_curve(curve) == 0)
return gnutls_assert_val(GNUTLS_E_ECC_UNSUPPORTED_CURVE);
_ecc_params_to_privkey(params, &ecc_priv);
R = ecc_new_point();
/* verify that x,y lie on the curve */
ret = ecc_projective_check_point(&ecc_priv.pubkey, TOMPZ(params->params[ECC_B]), params->params[ECC_PRIME]);
if (ret != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
memcpy(&zero.x, ecc_priv.Gx, sizeof(mpz_t));
memcpy(&zero.y, ecc_priv.Gy, sizeof(mpz_t));
memcpy(&zero.z, ecc_priv.pubkey.z, sizeof(mpz_t)); /* z = 1 */
/* verify that k*(Gx,Gy)=(x,y) */
ret = ecc_mulmod_cached(ecc_priv.k, curve, R, TOMPZ(params->params[ECC_A]), TOMPZ(params->params[ECC_PRIME]), 1);
if (ret != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
if (mpz_cmp(ecc_priv.pubkey.x, R->x) != 0 || mpz_cmp(ecc_priv.pubkey.y, R->y) != 0)
{
ret = gnutls_assert_val(GNUTLS_E_ILLEGAL_PARAMETER);
goto ecc_cleanup;
}
ret = 0;
ecc_cleanup:
_ecc_params_clear(&ecc_priv);
ecc_del_point(R);
}
break;
default:
ret = gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
}
return ret;
}
/* Decodes an DSA privateKey and params from a PKCS8 structure.
*/
static int
_decode_pkcs8_dsa_key(ASN1_TYPE pkcs8_asn, gnutls_x509_privkey_t pkey)
{
int ret;
gnutls_datum_t tmp = {NULL, 0};
gnutls_pk_params_init(&pkey->params);
ret = _gnutls_x509_read_value(pkcs8_asn, "privateKey", &tmp);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret =
_gnutls_x509_read_der_int(tmp.data, tmp.size,
&pkey->params.params[4]);
_gnutls_free_key_datum(&tmp);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret =
_gnutls_x509_read_value(pkcs8_asn,
"privateKeyAlgorithm.parameters",
&tmp);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret =
_gnutls_x509_read_pubkey_params(GNUTLS_PK_DSA, tmp.data,
tmp.size, &pkey->params);
_gnutls_free_datum(&tmp);
if (ret < 0) {
gnutls_assert();
goto error;
}
if (_gnutls_mpi_cmp_ui(pkey->params.params[0], 0) == 0) {
gnutls_assert();
ret = GNUTLS_E_ILLEGAL_PARAMETER;
goto error;
}
/* the public key can be generated as g^x mod p */
ret = _gnutls_mpi_init(&pkey->params.params[3]);
if (ret < 0) {
gnutls_assert();
goto error;
}
ret = _gnutls_mpi_powm(pkey->params.params[3], pkey->params.params[2],
pkey->params.params[4], pkey->params.params[0]);
if (ret < 0) {
gnutls_assert();
goto error;
}
pkey->params.algo = GNUTLS_PK_DSA;
pkey->params.params_nr = DSA_PRIVATE_PARAMS;
ret =
_gnutls_asn1_encode_privkey(&pkey->key,
&pkey->params);
if (ret < 0) {
gnutls_assert();
goto error;
}
return 0;
error:
if (pkey->params.params_nr != DSA_PRIVATE_PARAMS)
_gnutls_mpi_release(&pkey->params.params[4]);
return ret;
}
/* S = (B - k*g^x) ^ (a + u * x) % N
* this is our shared key (client premaster secret)
*/
bigint_t
_gnutls_calc_srp_S2(bigint_t B, bigint_t g, bigint_t x, bigint_t a,
bigint_t u, bigint_t n)
{
bigint_t S = NULL, tmp1 = NULL, tmp2 = NULL;
bigint_t tmp4 = NULL, tmp3 = NULL, k = NULL;
int ret;
ret = _gnutls_mpi_init_multi(&S, &tmp1, &tmp2, &tmp3, &tmp4, NULL);
if (ret < 0)
return NULL;
k = _gnutls_calc_srp_u(n, g, n);
if (k == NULL) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_powm(tmp1, g, x, n); /* g^x */
if (ret < 0) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_mulm(tmp3, tmp1, k, n); /* k*g^x mod n */
if (ret < 0) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_subm(tmp2, B, tmp3, n);
if (ret < 0) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_mul(tmp1, u, x);
if (ret < 0) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_add(tmp4, a, tmp1);
if (ret < 0) {
gnutls_assert();
goto freeall;
}
ret = _gnutls_mpi_powm(S, tmp2, tmp4, n);
if (ret < 0) {
gnutls_assert();
goto freeall;
}
_gnutls_mpi_release(&tmp1);
_gnutls_mpi_release(&tmp2);
_gnutls_mpi_release(&tmp3);
_gnutls_mpi_release(&tmp4);
_gnutls_mpi_release(&k);
return S;
freeall:
_gnutls_mpi_release(&k);
_gnutls_mpi_release(&tmp1);
_gnutls_mpi_release(&tmp2);
_gnutls_mpi_release(&tmp3);
_gnutls_mpi_release(&tmp4);
_gnutls_mpi_release(&S);
return NULL;
}
